Dual firing rate oil burner with nozzle purging means



Y 5 J. A. LOGAN 2,516,052

DUAL FIRING RATE OIL BURNER WITH NOZZLE PURGING MEANS Filed Dec. 30, 1946 a a I! e6 2/ it T 56 J2 1 32 J0 az 4 .25 J6 16 e4 37 as 21 131? a i: J (9 6 o INVENTQR was! A. log/w ATTOR EYS Patented July 18, 1950 I )UAL FIRING RATE OIL BURNER WITH NOZZLE PURGING MEANS Joseph A. Logan,I-Iadley, Mass, assignor'to Gilbert & Barker Manufacturing Company, West Springfield, Masa, a corporation of Massachusetts Application December 30, 1946, Serial No. 719,164

This invention relates to improvements in oil burners of the intermittently-operated type, such as are adapted for house heating service, wherein two oil-atomizing nozzles are employed and are adapted for operation alternately.

The invention has for its object the provision in a burner of the class described of valve means for selectively connecting the nozzles to the pressure side of the fuel supply pump and concurrently purging the unselected nozzle by connecting it to the suction side of the pump.

The invention will be disclosed with reference to the accompanying drawings in which:

The figure is a diagrammatical view of an oil burner embodying the invention.

Referring to Fig. 1 the burner includes two nozzles I and 2, both of the oil pressure atomizing type. These nozzles I and 2 may have different capacities. As an illustration, the respective capacities may be 1 and 2 gallons per hour. These nozzles are mounted side by side near the outlet end 3 of the air tube 4 of the burner. Oil is supplied to the nozzles by means of a pump 5, which draws in oil from a suitable supply tank (not shown) through a suction pipe 3. The pumped oil is forced outwardly through the casing of a by-pass valve 1 into the casing of a cut-off valve 8. The cut-off valve opens when the pumped oil attains a predetermined minimum pressure, say 85 pounds per square inch, and allows oil to flow into an outlet pipe 9 and thence to the nozzles as will be later described. The by-pass valve I opens when the pumped oil attains a predetermined maximum pressure, say 100 pounds per square inch, and allows some of the pumped oil to fiow through a by-pass I back to the suction side of the pump, as to pipe 6. Th valve I serves to regulate the pressure of the oil supplied to the nozzles and to maintain such pressure constant at the desired predetermined value.

The nozzles I and 2 may be used one at a time. They are adapted to be connected to the pressure side of the pump by a valve contained in a suitable casing II. This valve comprises two inter-- connected discs I2 and I3 slidable in a cylinder I4 in casing I I. A spring I5 yieldingly holds this valve in the illustrated and low firing rate position. A solenoid I6 is adapted, when energized, to move its core H, which is fixed to the stem of the aforesaid valve, and move the valve into its other and high firing rate position. With the valve in its low firing rate position, oil from outlet conduit 9 enters through a passage I 8 into cylinder I4 at a location between discs I2 and I3 and passesinto a passage I9, leading-tea valve 2 Claims. (Cl. 158-363) chamber 20 in casing II and thence through a conduit 2| to the low rate nozzle I. There is a float valve 22 in chamber 20 which will open to permit fiow toward the nozzle. The nozzle 2 is connected by a conduit 23 with a valve chamber 24 in casing I I and thence by a passage 25 in said casing to cylinder I 4, opening into the latter at a location above the disc I3, when the latter is in its low firing rate position, and therefore flow of oil intopassage 25 is prevented. When the valve I2, I3 is moved to its high firing rate position, the disc I3 will lie above passage 25 and disc I2 will lie above passage I9 and below passage I8. Thus, the supply of oil to the low rate nozzle I will be cut oil and the passages I8 and 25 will be connected to supply oil to the high rate nozzle 2. There is a float valve 23 in chamber 24, which will open to permit oil to flow to nozzle 2. It will thus be seen that by actuation of valve I2, 53, thepressure side of pump 5 can be connected either to the low rate nozzle I or to the high rate noz-.

Zle 2.

Air for combustion is supplied by a fan 21;

located within a casing 28 which connects with tube 4. The inlet to the fan is shown at 29. Such inlet is controlled by a shutter 30, located within a hollow housing 3 I, having air inlet open ings 32. The shutter is threaded on a screw 33,

which is mounted for rotatable as well as axial pivoted at 36 and having its other end forked to' This forked end is adapted straddle screw 33. to engage a nut 31 on the screw and movethe latter axially outward. The extent of axially outward movement will depend on the position'of nut 37 on screw 33 and the high firing rate posi-' tion of the shutter may be adjusted with precision by manual adjustment of nut 31.

An electric motor 38, which is secured to fan casing 28, drives pump 5 and fan 21 by means of a suitable transmission, represented merely conventionally in Fig. 1 by the shaft 39. The

motor is controlled in any suitable way, usually by means of a room thermostat switch 40 in the conventional manner. For example, the switch 40 is connected in series witha relay coil 4| in a circuit which is supplied from the secondary A2 of a transformer and which includes wires 43, 44 and 45. The primary 46 of this transformer is connected by wires 4'! and 48 to line wires 49 and 50, respectively, which lead from a suitable source of electricity. The relay coil 4|, when energized by the closing of thermostat switch 40, actuates a switch 5i to close a circuit to motor 38-, which circuit may be traced as followsfrom line wire 50 by wire 52, switch 5|, wire 53, motor 38 and wire 54 to line wire 49.

Ignition of the combustible mixture may be efiected by sparks produced across a pair-of electrodes 55, suitably mounted in tube 4 in proper igniting relation with the spray from either nozzle. These electrodes are connected by a pair of wires 56 to the secondary 51 ofa suitable ignition transformer. The primary 58 of this transformer is connected by wires 59 and 6D *to the motor wires 53 and 54, respectively. The ignition means is thus rendered active simultaneously with the motor 38.

"The valve i143, which varies the firing rate, maybe actuated manually or automatically in various "ways'as desired. For example, it may-be actuated automatically in response to outdoor temperature to provide for the high firing rate in severely cold weather and for the low firing rate in milder weather. For this purpose, a rthermostat switch viii, located to respond to outdoor temperatureis arranged to close a circuit to the valve shifting solenoid i6,-whenever the outdoor temperature falls sufiiciently low, say for example 20 F. This circuit may be traced 'as follows-from line wire 50, by Wire 52, switch 5|, wire 53 as far as a wire 62, wire 62, thermostat switch El, wire53, solenoid IB'and wire 64 to line wire 49. This circuit is dominated by relay switch 5| and thus by room thermostat switch lfl. That is, the outdoor thermostat switch 6| may close if the temperature falls low enough and thus predetermine a high firing rate but the shift to-a high'firing rate will-not occur until 'the room thermostatswitch Mlcloses and starts the burner. Then, and then only, will solenoid 'l the energized to shift valve i2. i3 to position to produce ahigh firing rate.

The'firing rate selector valve 12, 13 may also be operated manually if desired. Many of the benefits of the dual firing rate burner can be had even if the selector valve has to'be shifted manually. For convenience, the manual shifting may be effected by remote control. For example, a'push button switch 65, connected by wires '66-'and'6l to the :wires 62 and '63, serves in the same manner as the thermostat switch 6! to connect the solenoid l5 fin circuit so as tofbe energized when the room thermostat. switch 48 closes ona demand for heat from the burner. This push "button switch. may be located at any convenient point'in one of the living rooms of the house and it enables the selector valve to be shiftedwithout going'into the cellar 'to reach the burner. It is, however, lobvious'that the valve 12, It might be operated by a hand-lever (not shown) located at the'burner.

-.-In the practical. operation of a burner of the type described the weather conditions are often such that the burner may operate at the low firing rate for many consecutive days. And it is also true, that the'burner can operate at the high firing rate fortlcng-intervals and even :forsseveral consecutive days. This is one reason'why automatic shifting of the :firing rate selector valve is not so essential and manual shifting of this valve iiS -practica1. There is, however, a decided 4 disadvantage in allowing one nozzle to remain idle for long intervals while the other nozzle is operating. The idle nozzle and its feed conduit remain filled with oil which is not in motion.

Heat from the combustion produced by the other nozzle is reflected back and heats up the oil in the idle nozzle and in the immediately adjacent portion of the feed conduit. Some of the heat, reflected back as described to the nozzle and its feed conduit, will be dissipated to the air stream flowing in tube '4, but unless the heat is dissipated as fast as it is received, which is not likely, the temperature of the motionless body of oil in the nozzle and feed conduit will increase, and, if the temperature gets high enough, the oil will crack and carbon will be deposited in the nozzle or its feed conduit. Carbon deposits in the nozzle or in the feed conduit will eventually cause stoppage of the nozzle or its feed conduit and render the nozzle inoperative.

This invention overcomes the difiiculty "describedby providing for the removal of oilfrom either nozzle, when it is not in use, :and forzthe withdrawal of oil from at least that portiongof :the feed conduit which isexposed .to high heat-from the burners flame. One way of accomplishing thisresult is to connect each nozzle'to the suction sideof the pump5 when the other nozzle-is con nected to the pressure side. This may be offected by the selector valve 12, 13, operating :in connection with suction ports 68 and 69 'inlcylinder l4. These ports are interconnected'by a pas sage ii] in casing 1 I and such-passage is connected by-a conduit N to the by-pass pipe it] which in turn connects with the suction conduit -6 or pump 5. Acheck valve H is interposed inaconduit l-i toprevent back flow'of oil from-the-suppl y tank under gravity head. When this selector valve is in its low firing rate position, the'lower suction port 69 is blocked off by valve disc l2. The upper suction port 684s connected-to conduit 25, since'both this port-and conduitslie above fthe valve disc i 3. Hence, suction is applied to'the nozzle its conduit 23, valve chamber 124' and conduit 25. The float valve 26 will be open to allow withdrawal of the oil "by the suction of pump 5. Such withdrawal continues until the oil level in chamber 24 falls low enough to allow valve 25 to close. The nozzle 2 and "its =feed conduit 23 will then have been completely emptied. The valve '25 closes to prevent entry of air into the pump. When theburner is later started up at the high firing rate, the air in chamber 24 and conduit 23 will be readily driven out through the nozzle 2. 'When the selector valve is shifted to itshigh firing rate position,'the valve'disc it blocks off the upper suction port 88 and valve disc i2 rises above "the lower suction port 69 and above the entrance end of passage l9 and thus connects the latter to the suction'side of pump 5. The float-valve 22 being then :open, oil is withdrawn from nozzle I and its feedconduit 24 until the level in chamber 20 falls low enough to allow valve 22 to'close. The low rate nozzle l and its feed conduitwill then have been completely emptied. 'The arrangement thus insures the emptying of either nozzle and .its feed conduit when-either one is not connected to IE- oeiveoil from the pump.

In the operation of the invention thewbumer is started up automatically 'by room thermostat 40 when-there is ademand for heat. Oil-willfbe supplied by pump 5 to nozzle "or 2 depending on whether either the outdoor thermostat switch 61 or theswitch 65 is open or closed. If :both

these switches are open, the burner will be operated at the low rate while if either switch is closed, the burner will operate at the high rate. Air will be supplied by the fan at a high or low rate according to whether the selector valve is set for high or low rate firing. The air supplied through tube 4 will mix with the atomized oil emitted from nozzle I or 2, as the case may be, and the combustible mixture will be ignited by a spark produced between the electrodes 55. When either nozzle is connected to the pressure side of the pump 5, the other nozzle is connected to the suction side of this same pump and the idle nozzle and its oil feed conduit are emptied of oil back as far as the float valve chamber 20 or 24 as the case may be. The float valves 22 and 26 serve to close their oil feed conduits when oil has been withdrawn from their respective chambers 29 or 24 down to a predetermined level. These float valves serve to prevent air, which enters the idle nozzle and passes into its oil feed conduit, from reaching the valves 1 or 8 and pump 5. Any air entering the nozzle and its oil feed conduit up to the point described is readily driven out when that conduit is subsequently connected tothe pressure side of the pump.

The invention has been described in connection with a pressure atomizing burner of the dual firing type as an illustrative exampleof one important use. Another use for the invention is in connection with a burner of the same type where the two nozzles may be of the same size and one is provided as a standby nozzle for use when the other nozzle becomes disabled. Obviously, it is important for the same reason to withdraw oil from the standby nozzle and the immediately adjacent part of its oil feed conduit when such nozzle is idle, and the same means, herein disclosed, may be used for the purpose. The invention is generally applicable wherever the pressure atomizing burner has more than one nozzle and all nozzles are not always operated at the same time. If one nozzle lies idle, while another is operating, the invention is needed in order to withdraw oil from the idle nozzle and avoid the possibility of trouble due to carbonization and this, of course, is true regardless of whether the nozzles have the same or different capacities.

' Having disclosed the invention, I claim:

1. In an oil burner, an oil supply pump, two oil conduits, an atomizing nozzle on one end of each conduit, and a valve for connecting one o the other of said conduits at their other ends to the pressure side of said pump to supply oil under pressure to a selected one of said nozzles, said valve when moved to connect the conduit of one nozzle to the pressure side of said pump being operable to connect the conduit of the othe nozzle to the suction side of said pump, whereby to purge the unselected nozzle.

2. In an oil burner, an oil supply pump, two oil conduits, an atomizing nozzle on one end of each conduit, a valve for connecting one o the other of said conduits at their other ends to the pressure side of said pump to supply oil under pressure to a selected one of said nozzles, said valve when moved to connect the conduit of one nozzle to the pressure side of said pump being operable to connect the conduit of the other nozzle to the suction side of said pump, whereby suction may be applied to the unselected conduit to purge the unselected nozzle, and a float valve located in each conduit between its nozzle and said valve and operable to close such conduit after oil has been drawn out of it up to the float valve and prevent air from entering the pump.

JOSEPH A. LOGAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,858,302 Marshall May 17, 1932 2,168,680 Nordgren Aug. 8, 1939 2,233,934 Backhouse Mar. 4, 1941 2,241,327 Selby May 6, 1941 2,315,412 Galumbeck Mar. 30, 1943 2,347,843 Rayfield May 2, 1944 2,367,319 Wahlberg Jan. 16, 1945 2,390,902 Vollrath Dec. 11, 1945 2,403,230 Nagel et al July 8, 1946 FOREIGN PATENTS Number Country Date 14,234 Australia July 4, 1928 

